After tinkering with the grill, I ditched it as I was not happy with the thickness of the grill walls themselves and the somewhat flimsy feel of the grill when compared to the Weber product. In short, the Weber grill just seemed more solidly put together than the UniFlame product. And a more rugged product is a nice option I may potentially need at some point........

Not as major of a concern is that the adjustable vent in the Uni Flame grill is directly in the center of the dome, where screws to hold whatver type of volume minimizer and/or airflow director would be screwed into (requiring some additional meddling).

Just this weekend, I obtained a 22.5" Weber black kettle grill in excellent condition for $49 on Craigslist. Legs are off, measured out and marked the bottom where I will cut the hole out and also the side vent. Have pre-drilled and tried out some various sized pizza pans in the ceiling, as well as the ash catcher. I just need to go pick up a RotoZip from a neighbor down the street to make the cuts (I thought I would have the Roto this weekend to finish and fire it up!) I have everything else I need to finish the LBE, as well as a few extra pieces to make additional modifications, if needed.

I'll post more pics of the construction and finished LBE here when finished. In addition, I'll post all pictures of future pizzas here as well. The pizzas I am making do not fit the definition of Neapolitan, nor would they be considered New York-Neapolitan either, so the Neapolitan forum would not be appropriate.

More later. Getting excited and thrilled to have the Weber. It's a well made product.

Well, I fired up the LBE today for the very first time and.....mostly a pizza fail.

Pics of the LBE to follow, but some potential problem areas:

1. I made a cutout of the top of the bottom half of the grill on a piece of sheet metal and have that lying on my grill grate immediately underneath my pizza stone (I inverted the grill on a roll of galvanized sheet metal, drew a circle and cut that out). This blocks air except at the back of the grill. I think the space I left at the back is not wide enough to allow enough hot air to circulate over the pizza and to heat up the stone effectively.

2. My pizza stone was resting directly on the metal directional plate mentioned in #1. I think this kept the stone from reaching high enough temps as no air could reach directly under the stone. Some nuts or small pieces of quarry stone to slightly elevate the stone off of the metal cutout would allow some air to get under the stone. After 30 minutes of heat at minimum on my dial, stone was only at 535°F. I had troubles getting the stone northwards of 600°F even at full tilt.

3. The top of the stone is not flush with the top of the bottom part of the kettle. I need to raise the grill grate appropriately. This would help the air to be closer to the pizza as the air exits the side/front vent of the grill top.

Once I tool with 1, 2 and 3 I'll start dialing in the roof of the oven.

Lots of peeps in the kitchen today. This pizza only marginally approached where I want to go....but I guess not a complete disaster as I was worried if I would be able to make an edible product with my first go around with the LBE. This is a simple white pizza with mozzarella, buffalo mozzarella, parmigiano-reggiano, salt, garlic (garlic & mootz DO work together I tell ya!) and a DeMarco-ish amount of olive oil on the pie. Too heavy handed with the olive oil!

Back to the drawing board for improvements. The sound of the heat banging out of these things when the dial is set to full throttle after launching a pie is pretty friggen cool! It was hot today but you could feel the heat of this thing just standing in proximity to it.

Villa Roma, you are the man! Thank you for laying down the inspiration that got this whole train rolling through pizzadom.

scott123

If the hearth is sitting directly on the deflector plate, unless the plate is heavily warped, it shouldn't be doing much deflecting because of the contact/conduction involved. If you raise the stone, it will take even longer to pre-heat.

Wow! If that pizza is a failure, Then I don't know what a success looks like! What exactly did you not like about it? How long did it bake?

Thanks Ev.

The pizza took entirely too long to bake....timed on a stopwatch at 4:14. That's not a terrible time to cook a pizza in, but not for this dough, which was 100% Caputo 00 Pizzeria flour. A little too leathery on the outside, too pale all around and too dry inside.

Here is the current LBE, about to undergo some more fine tuning, particularly on the dome, which is mostly just conceptual to get an idea of what is going on with airflow, etc.

I haven't had much time to get this together, having to piece meal the work together over 15 minutes here and 15 minutes there over several weeks just to get it to this state. It’s definitely a “rough draft” at this point.

I think the heat deflector/flower pot is a potential major culprit in my heat issues.

In pictures

1. The bottom of the grill. 12” hole on bottom and resting on top of the Bayou Classic Cajun Cooker SB-10 model propane cooker many of us LBE peeps use. 20psi high pressure cooker. 185,000 BTUs.

I drilled some screws (seen in the picture) higher than the standard top grate holders already in the grill to bring the stone closer to the top of the bottom portion of the kettle.

2. Flower pot deflector filled with sand. The terra cota disk the pot sits on is on is 8” in diameter. The initial bake cracked the pot holder in half (you can see the crack in the bottom left quadrant of the pot holder)

3. Top of grill grate clearance from top of flower pot = ¾” (approx).

I see this as a potential major problem, as there is likely not enough airspace between the top of the flower pot and the bottom of the cooking surface to allow heat to circulate under the stone. Temperature readings of the stone to the sides and front-back of center point were higher by a meaningful amount….I’m guessing for this reason.

I need a lower deflector. Perhaps a shorter pot or a cast iron skillet with the handle hack sawed off like Mmmph has in his LBE.

4. Cut out piece of galvanized sheet metal to direct airflow to the back of the grill. Already some discoloration after the first bake.

5. Clearances of sheet metal directional plate. About 2.75” at center point and about 2” as it nears the sides of the bottom portion of the kettle.

This may need to be wider perhaps? Think I will fool with the flower pot/deflector first before adjusting the size of the gap on this directional plate.

Wondering if there needs to be a little airspace between the metal plate and the stone. May tinker with this after fooling with some other areas first.

6. Dome. This is very rough right now. An inverted 19” pizza pan is directly against the dome. Under that is a 13” pizza pan that I just bent a little to direct heat downwards at the back of the grill (on top of the lip of the pizza) and I also bent the 13” pizza pan more gradually towards the front of the grill like Mmmph has in his LBE.

I am going to more carefully construct a new deflector piece tonight and tomorrow night to get more precise downdraft on the pizza.

8. Bottom of 19” pizza pan is about 1.5” from the top of the side vent.

9. The top of the pizza stone is about 2 3/4” from the top of the side vent. This means the 19” pizza pan creates a roof which is about 4 ¼” from the top of the pizza stone/cooking surface.

As you can also see from picture #9, the top of the pizza stone sits about ¾” below the bottom lip of the side vent. I’m thinking of raising the screws in the bottom portion of the grill to make the top of the pizza stone flush with the bottom of the side vent. This would make the distance between the pizza stone and the roof (pizza pan) closer to 3 ½”. I bet this would help with cooking and stone heat a good bit.

The final pic was taken a year ago of my beloved Rottweiler Ruby, a rescue who travelled a million miles from her abused beginning, who we had to put down nearly a year ago today (July 10th). You can see how much of a sweetheart she was just looking into those eyes. Best dog ever. That’s where the name Pizza Ruby came from.

Once I get the LBE dialed in, I have some cosmetic work I plan on doing. Using some 1/16” modeling tape and high temp spray paint to create a tile effect over the grill something like the Ferrara and Napoletano wood fired ovens we all drool over.

Back to the drawing board and thanks for any pointers anyone can point out which may improve my results. It all ultimately comes down to trial and error.

I believe that the metal deflecting plate shown in picture 7 needs to have a bit larger cutout. Looks like most of the heat / hot air is kept below the plate. When the burner is running, the majority of hot air should be coming out the vent hole, not out of the bottom. You could check it with your hand and decide if the deflector is deflecting to much. Otherwise, I see nothing else wrong with it.

scott123

1. Lose the planter. A deflector really should be either the same size or larger as the stone. The steel plate might not have enough mass to deflect heat absolutely perfectly on it's own, but I definitely think it's worth a try and should work well.

2. Propping a stone hearth on a deflector is a losing equation. Whatever you use as posts will either be metal, and, via conduction, give you hot spots on the hearth, or... it will be stone or ceramic and give you cold spots. It's better to support the deflector in some way from below. I would put the steel plate at a slant. Rest the front on the bottom grate and the back (opening) on two screws about an inch below the hearth grate. At an angle, the opening will increase, so you shouldn't have to trim any off the length, but you will have to reshape the sides. Definitely start with a cardboard dummy, trimming it so that it fits.

3. To hit Neapolitan bake times on the top, you're going to need to rework the ceiling. An aluminum pizza pan isn't going to give you much thermal mass and the 1" or so gaps on each side isn't going to direct much air over the top of the pizza and out the vent. A lot of heat is going to go up and around which is not ideal. In Norma's Weber mod thread, I recommended replacing the ceiling with a 1/2" cordierite lid, resting on a galvanized steel strip running 3/4 of the outer circumference of the grill. I'm not saying this your solution, but, whatever you go with, you need good air flow (as little gaps between the false ceiling and lid as possible) and some thermal mass so it can radiate a little heat down on the pizza.

Lastly, here's 2 safety issues to be aware of

1. With a 185K btu burner, it's highly likely that you can reach sufficient temps to vaporize zinc. As Gene warned me in another thread, this is something you do NOT want to breath in. I would choose a day with a little bit of a wind, crank the heat, stand upwind and let it burn a bit of the zinc away, monitoring it carefully.

2. With a 185K btu burner, it's highly likely that you can reach sufficient temps to melt aluminum. If you're careful, you could probably avoid it, but, as you amp the heat for Neapolitan pies, you really don't want to be worry about molten aluminum.

2. …I would put the steel plate at a slant. Rest the front on the bottom grate and the back (opening) on two screws about an inch below the hearth grate. At an angle, the opening will increase, so you shouldn't have to trim any off the length, but you will have to reshape the sides…

Scott, it sounds like the plate should be positioned somewhat similar to what Chau did in his LBE. In Reply #10 of his LBE thread (http://www.pizzamaking.com/forum/index.php/topic,13036.msg127390.html#msg127390) you can see an angled deflector plate. What you are mentioning is a plate which is even more angled than Chau’s (the bottom of his slanted deflector sits nearer to the midpoint of the burner, not all the way to the front edge)

Although I believe Chau may have (potentially) mentioned his deflector plate actually slowed down pre-heat times….is this correct Chau or did you mean the circular metal directional plate lying on top of your upper grate?

3. To hit Neapolitan bake times on the top, you're going to need to rework the ceiling. An aluminum pizza pan isn't going to give you much thermal mass and the 1" or so gaps on each side isn't going to direct much air over the top of the pizza and out the vent….

Scott, my 19” pizza pan has no gaps around the edges…the edges are flush with the dome as it slopes upwards (where the dome starts getting smaller in diameter) near the top.

Axner sells a 21” diameter x ¾” thick cordierite kiln shelf for $30..that would really drop the ceiling down…but would be heavy. Maybe I need to try this too.

Member Mmmph has a larger pizza pan in the ceiling, with an additional 15” pizza pan bent to form a “scoop” or heat downdraft director to help cook the inner portion of the cornicione as seen here:

Mmmph is using some malted flour in his formula to get these bakes and crust coloration, but a faster cook time is possible. I’m not hell bent on having to do a 90 second pizza (I have no probs cutting in some AT flour into the mix), but I would like the opportunity to do it with all Caputo 00 if I desire.

Actually, the simplicity of Mmmphs set up (cast iron skillet deflector, just a stone resting on tin foil burgers) looks like it allows a ton of heat to get up and around the stone.

1. With a 185K btu burner, it's highly likely that you can reach sufficient temps to vaporize zinc. As Gene warned me in another thread, this is something you do NOT want to breathe in. I would choose a day with a little bit of a wind, crank the heat, stand upwind and let it burn a bit of the zinc away, monitoring it carefully.

2. With a 185K btu burner, it's highly likely that you can reach sufficient temps to melt aluminum. If you're careful, you could probably avoid it, but, as you amp the heat for Neapolitan pies, you really don't want to be worry about molten aluminum.

Scott, excellent points that I have not fully considered!

Most of the screws I have seen in Home Depot, especially the machine screws I have used in my set-up, do indeed have Zinc in/on them….mentions it right on the package ..”Zinc plated machine screws”. And to think I kept looking right into the side vent from a distance as the first pie was cooking….maybe inhaling that stuff!

Other than the screws, what other Zinc would there likely be…are you talking about vaporizing any Zinc that may be part of the mix of materials which makes up the grill or the galvanized sheet metal deflector plate itself? (that question likely reveals me as a metals dimwit).

Molten aluminum does not sound good. And at this point I am turning on the “dump valve” of the Cajun cooker all the way on once I launch a pie.

The safety issues of materials is likely a great candidate for its own thread, given we are often inviting other peeps over for pizzas and some of us envision potentially using the LBE at farmers markets, etc.

If I get injured because of my own pizza obsessions, that’s one thing. But having others exposed to health risks because of it is unacceptable.

Kelly, yes I did have a deflector plate that I removed. At the time it seem to shave off about 5min on the preheat times from 20 down to 15m. I haven't been using it lately, but lately it seems my preheat up times have crept back to 20m. I'll have to do some more testing again, with and without that plate.

If your preheat times are lengthy, it's either too much mass to heat or an airflow problem. Likely an airflow problem. I would either remove the obstructions or widened the path of/for air flow.

scott123

I think that plate, support by bolts, should give you good heat flow, allowing plenty of heat to reach/pre-heat the hearth, while still deflecting enough heat so that the hearth doesn't heat up too much during the bake and the heat goes up and over the pizza, baking the top.

Galvanized steel is steel that's been coated with zinc. So the potential danger is the fumes from the vaporization of the galvanized coating. As I said before, crank the burner, stand upwind and let it burn away some of the zinc on the steel plate. If, say, you're relatively certain that you're going to stick to 2 minute or less pies, then crank the burner for 3 minutes.

It seems like aluminum foil is a go to component for most LBEs. I'm not 100% certain that most LBEs have your kind of BTUs, though. I know Chau has a burner with similar BTU output and he learned the hard way about high temps and aluminum. In all fairness, though, if I can recall correctly, his molten aluminum occured with an aluminum deflector and not an aluminum ceiling. At least I think that was the case. A deflector, because it's right smack in front of the flame, is going to get a lot hotter. And, although I mentioned 'safety' regarding the aluminum, if it does melt, it's not really dangerous, it's just more of a hassle, as it could clog up your burner. If your ceiling did, perchance, melt and drop into the pizza, I'm certain you'd be aware of it and not serve it to your guests.

I couldn't tell from the photo that the pizza pan is flush with the side of the lid. Now that I know that at is, I think it's worth leaving the pizza pan in place for some experiments with the galvanize steel plate in the better deflection setup. You'll know pretty quickly if you need more top heat, and, if you do, then it'll be time to start looking into materials with better thermal storage such as cordierite.

The one thing I would do in relation to the ceiling is, as you've hinted at, is to raise the hearth. Raising the hearth will put it closer to the level of the side vent as well as bring the ceiling a bit closer. I would, say, raise it so that the top of the hearth is flush with the bottom of the vent.

Cast iron makes a great deflector, if you've got it on hand. I am a bit partial to an offset position, though, rather than a centered one, to encourage the heat to go up one side, over the pizza and out through the vent. Since you've got the galvanized plate already, I'd see what it can do. In the right position, I think it should redirect the heat up and over the pizza quite nicely.

Galvanized steel is steel that's been coated with zinc. So the potential danger is the fumes from the vaporization of the galvanized coating. As I said before, crank the burner, stand upwind and let it burn away some of the zinc on the steel plate. If, say, you're relatively certain that you're going to stick to 2 minute or less pies, then crank the burner for 3 minutes.

Scott, are you saying:

1. I should crank the burner to burn off the zinc once for 3 minutes before a session of pizza making begins and then proceed as normal? (meaning I would turn on the burner on high at the beginning of each session I make pizzas in)

2. I should crank the burner to burn off some zinc for 3 minutes before making each pizza?

3.I should crank the burner to burn off the zinc once for 3 or more minutes one time only, having possibly burnt out enough of the zinc to be able to proceed as normal over many pizza making sessions from there on out?

I don't think you are alluding to #3.

Thanks! --K

EDIT: Scott, there are a variety of sizes of cast iron skillets and cast iron pizza pans which are pretty thin...thin enough to put into the roof of a LBE. Would the cast iron or the cordierite be a better choice with regards to radiating top heat down onto the pizza?

« Last Edit: July 08, 2011, 11:44:50 AM by pizzablogger »

Logged

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scott123

#3 One time only. My reasoning is that, since you'll be pre-heating with the burner turned down a bit, the only time where the zinc might hit vaporizing temps is during the bake, while the burner is at full throttle. If you're going to be doing two minute bakes, then exposing it to 3 minutes at full throttle will push it farther than any of the bakes will. Any zinc not burned out by the 3 minute blast shouldn't be burned off with regular 2 minute blasts.

Iron will give you more thermal mass in the ceiling and a darker color, with improved emissivity, two better traits in a ceiling. The iron has to be wide, though, so it sits at or close to the same height as you have now. Out of mass, emissivity and physical proximity, proximity wins by a landslide. Thanks to the Inverse-square law, the further the ceiling is from the pizza, the paler the top of the pizza is going to be. A WFO can work with a 13"ish ceiling because of the 1000+ deg. temps, but your ceiling, with a bottom heat source, isn't going to hit that, so the closer it is to the pizza, the better.

scott123

Conductivity is so elegant and simple to understand and predict. When I put the pizza on the pre-heated stone, I can literally visualize the vibrating molecules in the stone causing the molecules in the dough to vibrate as well. Conduction is just so straightforward. Radiation, not so much. Did you know that the manner in which a material absorbs radiative energy involves quantum physics? You, know particles, waves, a potentially dead cat in a box?

Anyway, I get the Inverse Square law, and I'm beginning to understand radiation a bit better than I used to, but I'm a long ways from understanding radiation as well as I understand conductivity.

If you've ever worn a black shirt and felt the heat on a sunny day or noticed snow melting faster on dark pavement than it does on lighter concrete, you'll have recognized darker color's superior ability at absorbing light waves/radiant energy. The same mechanism that makes dark colors superior absorbers causes them to be superior emitters as well. They can take it and they can dish it out. So, yes, darker colors = better emissivity. They're not better at heat retention, though. If they're shooting out more radiation energy than their paler cousins, then their temperatures will drop at a faster rate. Probably not that fast, though. Imo, conduction (stone to surrounding air) is a far more effective temperature killer than what might be lost to radiation.

Summing up, when choosing a hearth- don't worry about the color, as it's all about conduction and conduction is color blind. When choosing a ceiling, though, and you're in a situation where you need as much top browning chutzpah as you can muster, go dark.

Did you know that the manner in which a material absorbs radiative energy involves quantum physics? You, know particles, waves, a potentially dead cat in box?

Lol. Quantum foam makes me roam.....

Take a slitted, photosensitive box, make it completely devoid of photons, shoot only a single photon into said box and.....viola! The box still shows the interference pattern that would occur if a steady stream of photons (light) were shot into it. Of course this is due to the protons in a very close , but parallel plane/universe than ours creating the interference pattern!

Quantum physics, superstring, M Theory.....all that %$# can make a person's head explode. For the layman, The Elegent Universe is a great read to have on hand, even if now outdated.

Power went out overnight.....these bad boys are not going to be ideal, but I'm just trying to guage heating performance for now.

Going to do a test run with no planter and with the gap in the back of the flat, circular deflector plate (which is directly under the pizza stone) much wider to see what happens when there is little impediment to the flame.

Then I'll tinker with the angled deflector plate (Scott123 suggestion) and more tuned in ceiling action.

Interesting that last night Casey's Pizzas made his first appearance in Oakland, CA. With his two LBEs he knocked out 90 pizzas. That's not too bad at all for a pizza pop-up. Not bad at all. --K